1. Field of the Invention
The present invention relates to an image pickup device-equipped rear-view mirror in which an image pickup element is arranged behind a mirror element, and it provides improved image pickup performance, glare prevention and appearance (design), in addition to improved performance as a vehicle mirror.
2. Description of the Related Art
An image pickup device-equipped rear-view mirror in which an image pickup element is arranged behind a mirror element for the purpose of reducing the blind spot for a vehicle or monitoring the inside of the vehicle are proposed in Japanese Patent Laid-Open No. 5-294183, Japanese Patent Laid-Open No. 7-186831, Japanese Patent Laid-Open No. 2000-264128, and Japanese Patent Laid-Open No. 2000-236468. The techniques disclosed in Japanese Patent Laid-Open No. 5-294183 and Japanese Patent Laid-Open No. 7-186831 have an image pickup element in a door mirror, and also have a mirror element consisting of a half mirror, and it picks up an image of the sight of an area behind a vehicle by means of the image pickup element through the mirror element. The technique disclosed in Japanese Patent Laid-Open No. 2000-264128 has an image pickup element in an inner mirror, and also have a mirror element consisting of a half mirror, and it picks up an image of the sight of an area inside the vehicle by means of the image pickup element through the mirror element. Also, Japanese Patent Laid-Open No. 2000-264128 discloses that an infrared camera is used as the image pickup element, and that a cold mirror is used as the mirror element. The technique disclosed in Japanese Patent Laid-Open No. 2000-236468 has an image pickup element in a rear-view mirror, and also have a mirror element with its reflecting film removed at a part thereof, and it picks up an image of an area behind the vehicle by means of the image pickup element through the part in which the reflecting film has been removed.
According to a rear-view mirror using a half mirror, which is disclosed in Japanese Patent Laid-Open No. 5-294183, Japanese Patent Laid-Open No. 7-186831 and Japanese Patent Laid-Open No. 2000-264128, since the transmittance and the reflectance of a half mirror are incompatible with each other, it has been difficult to provide both a reflectance that meets the laws and regulations as a vehicle mirror and a transmittance for obtaining a sufficient image by means of an image pickup element. Also, according to a rear-view mirror using a cold mirror, which is disclosed in Japanese Patent Laid-Open No. 2000-264128, since a cold mirror has a reflectance close to 100% in the visible range, there is a problem in that headlight from behind makes a driver have the feeling of glare at night, obstructing the driver's safe driving. Furthermore, since a cold mirror has a large view angle dependency, the inside of the mirror may be seen through or a discontinuous part may arise in the tone of reflected light, depending on the position of the driver's viewpoint, and thus, there is also a problem of appearance (design). A rear-view mirror having a mirror element with its reflecting film removed at a part thereof, which is disclosed in Japanese Patent Laid-Open No. 2000-236468, has a problem in that the backward visibility may deteriorate since a part of the mirror element does not function as a mirror. Also, the mirror element with a part of its reflecting film removed has a problem of appearance (design).
The present invention has been made in view of the aforementioned points, and is intended to provide an image pickup device-equipped rear-view mirror with improved image pickup performance, glare prevention and appearance (design), in addition to improved performance as a vehicle mirror.